In general, industrial air-conditioning apparatuses larger than domestic air-conditioning apparatuses use three-phase AC power. In such an industrial air-conditioning apparatus, an inverter is usually used to drive a load, such as a motor, provided in the air-conditioning apparatus. Since the input to the inverter needs to be DC voltage, it is necessary to convert three-phase AC power to DC power.
There have been proposed various apparatuses that convert three-phase AC power to DC power. For example, Patent Literature 1 discloses a boost three-phase full-wave rectifier that includes a circuit breaker capable of disconnecting three-phase AC power, a current detector configured to detect phase currents flowing through respective phase lines, boost inductors provided for the respective phase lines, a three-phase full-wave rectifying circuit including switching semiconductor devices connected in a three-phase bridge configuration, a smoothing capacitor, and a control circuit configured to perform high-frequency switching of the switching semiconductor devices according to a predetermined sequence. In this boost three-phase full-wave rectifier, diodes are connected so as to form a three-phase bridge circuit in which the phase lines between the circuit breaker and the respective boost inductors serve as inputs thereof, and positive and negative common lines of the three-phase full-wave rectifying circuit serve as outputs thereof.